Carbonaceous materials are oxidized when suspended in a solution containing iron(III)/iron(II), copper(II)/copper(I), chloride ion, hydronium ion and a homogeneous cocatalyst. The organic carbon is converted to CO.sub.2 by oxidation with molecular oxygen or oxygen-containing gas, liquid or solid mixture.
U.S. Pat. No. 4,105,755 concerns reacting an ash-containing carbonaceous material, optionally an organic waste material, with a halogen, to form a halogen acid, and then decomposing the halogen acid to halogen (recycled) and hydrogen. The halogen acid is preferably decomposed electrolytically if this step of the reaction takes place as a separate step from the initial reaction of the ash-containing carbonaceous material and halogen.